1. Field of the Invention
Exemplary embodiments of the present invention relate to an arc discharge detecting circuit, a light source driving apparatus having the arc discharge detecting circuit and a method of driving a light source using the arc discharge detecting circuit. More particularly, exemplary embodiments of the present invention relate to a current-source type arc discharge detecting circuit, a light source driving apparatus having the arc discharge detecting circuit and a method of driving a light source using the arch discharge detecting circuit.
2. Description of the Related Art
Generally, in a liquid crystal display (“LCD”) apparatus, a light source generates light for displaying an image on an LCD panel. For example, the light source may be a fluorescent lamp such as a cold cathode fluorescent lamp (“CCFL”), an external electrode fluorescent lamp (“EEFL”) or a flat fluorescent lamp (“FFL”), a light-emitting diode (“LED”), or various other types of light sources.
A driving part for driving the light source typically converts a direct current (“DC”) voltage into an alternating current (“AC”) voltage according to a luminance-control voltage provided from an outside source, and provides a lamp with the converted voltage to turn the lamp on and to control a luminance of the lamp. In addition, the driving part detects a current flowing through the lamp and controls the converted voltage provided to the lamp based on the detected current thereof.
When the fluorescent lamp is used as the light source for the LCD apparatus, the driving part provides the fluorescent lamp with a high voltage to initially turn the fluorescent lamp on, e.g., the fluorescent lamp is provided with a high voltage start-up voltage. When a terminal of the lamp receiving the high voltage is not properly insulated or a contact resistance is generated between the terminal of the lamp and the driving part, an undesirable arc discharge may be generated. The arc discharge may have negative effects on an operation of a backlight assembly and may further possibly cause a fire or a smoke. In addition, the fluorescent lamp generally uses mercury (Hg) inside, so that the arc discharge may also cause environmental pollution via release of the internal mercury.
For preventing the arc discharge, after the driving part is manufactured, an inspector typically visually inspects an electric contact between the lamp and an electrode or alternatively to, or in addition to, visual inspection an arc discharge detecting circuit may be included within the display to stop an operation of the driving part when the arc discharge is generated.
The arc discharge detecting circuit typically used is connected at each of both electrodes of the fluorescent lamp, e.g., the positive and negative terminals thereof, so that the arc discharge detecting circuit is complicated and includes multiple duplicated parts. In addition, a voltage provided to the fluorescent lamp is divided by capacitors connected to both the electrodes and a voltage detected at the capacitors is output from the divided voltage at the capacitors to detect the arc discharge. Therefore, the detected voltage output from the divided voltage at the capacitors may have a low voltage level, and thus the arc discharge may be hard to detect.